1. Field of the Invention
The present invention relates to a thermal conductivity detector used in gas chromatography (GC), and a gas chromatograph.
2. Description of the Related Art
As a detector used in gas chromatography, a thermal conductivity detector (TCD) is known (for example, see JP 07-043356 A (reference document 1), U.S. Pat. No. 4,254,654 (reference document 2)). A thermal conductivity detector uses exchange of heat between a heating element (filament) and a fluid (gas) flowing around the heating element. Gas is introduced into a space where the heating element is accommodated, and is then discharged from the space.
The thermal conductivity detector is provided with at least two cell spaces where a filament element is arranged. The filament element is arranged in each cell space.
Reference gas flows through one of the cell spaces. Carrier gas flows through the other cell space, and sample gas which is an analysis target is thus introduced. Then, electrical output of the two filament elements is input to a detection circuit. At the detection circuit, a correction current according to the difference in the thermal conductivity caused by introduction of the sample gas flows. The thermal conductivity detector detects this correction current to thereby detect a sample.